This invention relates to casement windows and more particularly, to a vent-egress casement window.
Most fire codes pertinent to casement windows require a twenty inch minimum clear opening width and a 5.7 minimum square feet opening area. Most modern casement windows use concealed hinges which utilize a linkage system that in the fully open position locates the sash somewhat midway between the two jambs. Although this has the obvious advantage of allowing the exterior side of the sash to be washed from inside the building structure, it has the disadvantage of limiting the clear opening width of the window. There are at least three solutions to this problem which are commonly known in the trade: (1) the use of large windows with standard concealed hinges; (2) the use of windows with butt hinges; and (3) the use of windows with redesigned, concealed hinge linkages. Although the fire codes can be satisfied with the first solution, an excessively large window often detracts from the overall aesthetics of a building structure. The use of a large fire egress window as a part of a double or triple casement unit is also restricted. The use of windows with butt hinges instead of concealed hinges allows a large clear opening width, but the washing advantage is sacrificed. Redesigned concealed hinge linkages may move the window sash from the hinge side jamb a lesser distance than standard concealed hinges and satisfy the fire codes, but a suitable wash opening is sacrificed, and the degree to which the movement of the sash from the hinge side jamb can be lessened is limited. The limitation results from possible interference of the sash with the hinge side jamb as the sash is opened.